You might want to check out Dynalist. I've used it for project planning and idea dumps for a couple years and it's served perfectly for me. Saved my bacon with

You might want to check out Dynalist. I've used it for project planning and idea dumps for a couple years and it's served perfectly for me. Saved my bacon with school notes as well. As for lock-in, their paid plan includes daily experts so even if the service vanished, all my notes are safe as markdown files.